40-Fold increase in carcinogenic compounds in Gulf

Researchers from Oregon State University have found a 40-fold increase in polycyclic aromatic hydrocarbons (PAHs) between May and June just off the shore of Louisiana’s Grande Isle. The sampling device used by the research team was specifically designed to measure the fraction of PAHs in the environment that could make their way through a biological membrane. Dr. Kim Anderson, an OSU professor of environmental and molecular toxicology, had this to say:

This is a measure of what would enter into an organism. There was a huge increase of PAHs that are bio-available to the organisms – and that means they can essentially be uptaken by organisms throughout the food chain.

Water samples taken off the Mississippi, Alabama and Florida coasts – as well as air samples taken along the coast – also showed elevated levels of PAHs, but not nearly of the same magnitude. The samples taken in August were still being tested at press time. The operative question is how many of the PAHs have biodegraded in the interim. There were somewhere between 4 and 5 million barrels of oil spilled into the Gulf’s waters between April 20th and July 15th.

PAHs are a class of more than 100 hydrocarbon pollutants and 17 get particular attention because exposure can have harmful health effects. Almost every one of those 17 particularly toxic compounds experienced the 40-fold increase that the entire class did. Different organisms – plankton, fish, shellfish or humans – have different exposure risks to PAHs in the water according to the researchers. They also have different capacities to metabolize the PAHs. It’s not known how many of these toxic compounds actually ended up in the food chain. To make that determination will take more studies and research. It’s very important that the USDA make sure that the seafood that goes to market is safe to eat.

We have written in prior issues on the chemicals dumped into the Gulf by BP. Based on his findings and that of other researchers, Dr. Anderson suspects that the abundant use of dispersants by BP increased the bioavailability of the PAHs. In late July, we reported that scientists had found signs of an oil-and-dispersant mix under the shells of tiny blue crab larvae in the Gulf. It appeared at that point to be an indication that dispersants had broken up the oil into toxic droplets so tiny that they can easily enter the food chain. But two months later, those researchers have yet to finalize their conclusions. So the question remains open.

But the bottom line is that researchers testing the waters off Louisiana in June found hugely elevated levels of PAHs, some of which are known carcinogens. The thing we should all be concerned about is that the samples taken off the shore of Louisiana’s Grande Isle registered a 40-fold increase in PAHs between May and June. That’s not a good thing!